1. Field of the Invention
The present invention relates to a method of setting a print start position in a continuous form printing system such that when the printing system operates in a both-side print mode, the leading edge of a first page of the obverse side of a printing sheet of paper, which is printed by an obverse side printer, is matched to the leading edge of a first page of the reverse side of the printing sheet, which is to be printed by a reverse side printer.
2. Description of the Related Art
FIG. 1 is a view showing a sheet 1 with perforated folds. FIG. 3 is a perspective view showing how to set a print start position by use of a perforated fold 3. The setting of the print start position in the continuous form printing system will be described with reference to FIGS. 1 and 3.
A sheet position used when the printing operation starts is set in a manner that a perforated fold 3 or a toner mark 4 is set, by the eye, at a division 7 on a scale, which is representative of a print start position. The sheet position may also be set in the following manner. A leading edge 11 of a printing sheet as cut off along a perforated fold is detected by a sensor 14. The printing sheet is fed forward a specific distance from a position where the leading edge 11 is detected, and the perforated fold 3 is set at a page leading position 6 from which the printing operation will start.
FIG. 5 is a diagram showing a both-side printing system using a continuous form printing system. In the printing system, two printers are connected in series so that those printers print on a continuous form continuously, and a sheet reversing device 10 for reversing a surface of the continuous form from one side to the other is provided between those printers. In the case of a printing sheet 2 not having perforated folds, a page position is not fixed physically. Accordingly, the printing operation may start from a desired position. To print on both sides of the printing sheet 2 not having perforated folds, it is necessary to match a print position on the reverse side of a page of a printing sheet, which contains something printed on an appropriate location on the obverse side thereof, to a printing position on the obverse side of the page. The leading edge of the printing sheet 2 not having perforated folds is not fixed in position relative to the printing position. Accordingly, it is impossible to use the print start position matching method based on the leading edge detection of the paper. For this reason, the print start positions must be matched to each other by the eye and manual. However, the use of the eye results in an unsatisfactory accuracy of the print start position matching, and the matching operation by manual is unsatisfactory in operability.